forces - centre of mass (whatyouneed2know)

Question 1

what is the centre of mass?

Answer 1

the centre of mass of an object is the point on the object through which the mass appears to act

for example - on a metre ruler, 50cm would be the CoM

Question 2

how do you find the centre of mass?
(whole process)

Answer 2

1)
hang an object freely spinning; the shape will adjust itself so the CoM is directly beneath the pivot

2)
the imaginary line across the shape these points in the LINE OF ACTION - hanging a plumbline in front of the shape will show the line of action

3)
mark the position of the plumbline at the bottom of the shape and repeat at all corners or regular intervals around the shape

4)
draw lines connection each mark to its corresponding pinhole, the point at which the lines meet at is the CoM

Question 3

how do you test the CoM of a shape?

Answer 3

• balance the shape at the CoM with your finger
• push a pin through the CoM and spin it